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A LISTENER'S GUIDE TO DVD-VIDEO
Home | DVD Sound | |
DVD-Video doesn't just offer a better picture. It also provides vastly improved sound-and a lot more of it. Up to eight soundtracks, including different-language versions of a movie, can be included on the same disc. What's more, the soundtracks can carry anything from mono sound up to 5.1-channel surround sound, and use different digital audio coding technologies. Soundtrack Formats Sound Modes Some 5.1-channel decoder units and A/V receivers have playback mode displays based on these same icons. Some discs provide a variety of soundtracks using different sound modes. A movie disc, for example, might use 5.1-channel Dolby Digital for its English track, and Dolby Surround for other languages. Digital Audio Types Dolby Digital is categorized as a "mandatory" audio type, meaning it can be the only one used on a disc. Those that are categorized as "optional" can be used only when at least one soundtrack of a "mandatory" type is on the disc as well. Because all DVD-Video players are equipped with Dolby Digital decoding as standard, most DVD-Video titles have only a mono, two-channel or 5.1-channel Dolby Digital soundtrack as previously noted. Additional indicators or logos are displayed if soundtracks of more than one
audio type are present. The Dolby Digital track on such discs may be identified
by the Dolby Digital icon combined with a sound mode
icon. A disc can have for example, four soundtracks utilizing different sound modes and digital audio types. Playback The two-channel analog output is for connection to a TV, a two-channel stereo system, or a home theatre system with Dolby Surround Pro Logic decoding. The player will automatically create a Dolby Surround encoded, two-channel version of 5.1-channel Dolby Digital soundtracks. For mono playback, some players can also create a mono version at the listener's option. The digital output is for connection to an external unit, such as an A/V receiver, with 5.1-channel Dolby Digital decoding. Some players, have built-in 5.1-channel decoders for connection to a "5.1- channel ready" receiver. External 5.1-channel decoders, however, provide the greatest flexibility, and often superior sound as well. About Surround Sound Dolby Digital can deliver 5.1-channel sound from DVD-Video and DVD-ROM discs, laser discs, and digital TV broadcasts, satellite transmissions, and cable systems. It differs from Dolby Surround by providing two separate surround channels for greater realism, and an additional ".1" or "LFE" channel for low-frequency (bass) special sound effects. The LFE channel is sometimes incorrectly identified as the
"subwoofer" channel. While a subwoofer can be helpful in reproducing
low bass in general, it is not necessary to have one if one or more of the
speakers in the playback system have extended bass response. Without a
subwoofer, the LFE channel's bass effects can be directed to those speakers with
extended bass. Furthermore, not all multichannel soundtracks have the
".1" channel; it is used primarily for explosions, rumbles, and the
like on movie soundtracks, and is not present on all programs.
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